Such animals are herein also called polystomachic animals or ruminants. In connection with breading of domestic animals, such as pigs, calves, broilers, horses, etc it is previously known that living or viable lactic acid producing bacteria in many cases can replace antibiotic substances in admixture with feed compositions. The purpose of using this principle is to stabilize the intestine channel of the animal by an antagonistic effect based on a conflict between lactic acid producing bacteria and pathogenic bacteria. This is previously known for example in SE-A-6913996-2 which discloses the use of a preparation containing living bacteria in connection with domestic animals. Such preparations are generally called probiotics. The predominant part of probiotics are bacteria belonging to lactic acid producing lactobacills or streptococcs. A small part belongs to the genus Bacillus, for example Bacillus subtilis or Leuconostoc. The majority of these are homofermentative lactic acid fermenters. Bacillus completely diverges from lactic acid bacteria both as to a species and function; members thereof are to a great extent used for enzym production, for example amylase and protease. Nevertheless Bacillus is used in the form of spores for the same purpose as lactobacills, i.e. to stabilize the intestine flora and thus increase the yield by an improved feed rate and an improved meat yield. Among commercial preparations based on the principle mentioned above, there are mentioned LBC, Lactiferm, Adjulac (lactic acid bacteria) and Toyocerin (spores of Bacillus).
By tradition probiotics are not administered to milk producing ruminants. The reason is that such animals are considered to be very stable as to their intestinal function. The intestinal micro flora of ruminants is further very complicated and those skilled in the art have the general opinion that it is not possible to affect the bacterial balance in the rumen by way of preparations containing bacteria added externally but are of the opinion that said balance is controlled by the composition of the feed as a primary factor. In certain cases efforts have been made to use probiotics even in ruminants, i.e. against mastitis. Reference is made to U.S. Pat. No. 4,591,499, which discloses a method of controlling mastitis in mammals comprising introducing into the mammary gland an amount of non-pathogenic lactic acid producing live bacteria. This treatment is based on the utilization of a bacterial antagonism between non-pathogenic lactic acid producing bacteria and pathogenic bacteria, e.g. coli bacteria, inhibiting the growth of the pathogenic bacteria. A possible way of supplying ruminants with lactic acid bacteria might be with the aid of a silage, i.e. green feed, which has been fermented with lactic acid bacteria. However, during storage of silage the lactic acid bacteria die. Thus, in silage there is no probiotic effect of naturally occuring or added so called ensilaging inoculants (such products are available on the market) consisting of living lactic acid bacteria.